great, one down...
the speed issue is probably a corruption in the file.
this is the order of operations for checking the slow drawing problem:
1. determine if it is this file, or the program with the problem. do this by opening other files and checking the speed. if it appears it is the file, then go to 2, if the problem appears to be with the program, then go to 5.
2. make a backup copy of the file - better safe than sorry.
3. open the drawing, perform an audit (file-drawing utilities-audit). when prompted, allow acad to fix the errors that it finds. (did it find any?)
4. test to see if that helped. if so, great; if not, go to 7.
5. to repair your civil 3d will take about 15 minutes more or less and you will need to be out of the program. i don't know what operating system your pc has, i am using windows xp pro so the path may be a bit different for you. click start-control panel-add/remove programs. find the civil 3d entry and click change. next, select the "reinstall or repair" option and click next. select "repair errors in my...installation" and make sure the "restore my shortcuts" checkbox is checked, click next. and wait................
6. test to see if that helped.
7. post file in the "customer files (attachments)" discussion group. leave a description of how it performed before, how it performs now (specific commands that you have used that are slow), and what changed it (the attempt at watershed analysis). also post here that you have posted there so that i can check it out also.
there may be more after the above discovery, post, etc. we shall see.